Hún hjólar alltaf á hjólastígnum, jafnvel þegar gatan er tóm.

This is a very common Icelandic case question.

With á, Icelandic often distinguishes between:

• location: where something happens → usually dative
• direction/destination: movement onto something → usually accusative

Here, hjóla á hjólastígnum means she is biking on the bike path as the place where the action happens. It is not focusing on going onto the bike path. So hjólastígnum is in the dative.

If the meaning were more like she bikes onto the bike path, you would expect the accusative form instead.

The basic dictionary form is hjólastígur, meaning bike path or cycle path.

In this sentence, it appears as hjólastígnum, which is:

• singular
• definite → the bike path
• dative

So the ending -num reflects both the case and the fact that the noun is definite.

Hjólar is the 3rd person singular present tense of the verb hjóla.

So:

• ég hjóla = I bike / cycle
• þú hjólar = you bike / cycle
• hún hjólar = she bikes / cycles

Because the subject is hún, the verb must be hjólar.

In a normal Icelandic main clause, the finite verb usually comes early in the sentence, and adverbs like alltaf often come after it.

So:

• Hún hjólar alltaf ...

is a very natural word order.

This is related to Icelandic’s verb-second tendency in main clauses. The subject comes first, the finite verb comes next, and then adverbs often follow.

English learners sometimes want to compare it to English She always bikes..., where always often comes before the main verb. Icelandic does not have to place it the same way.

Jafnvel means even, and þegar means when.

Together, jafnvel þegar means even when.

It introduces a clause that adds contrast or emphasis: she bikes on the bike path in all situations, even when the street is empty.

Because gatan means the street, while gata means just street.

Icelandic usually adds the definite article to the end of the noun rather than using a separate word like English the.

So:

• gata = street
• gatan = the street

In this sentence, the speaker is referring to the street, so the definite form is used.

Adjectives in Icelandic must agree with the noun they describe in gender, number, and usually case.

The noun gatan is:

• feminine
• singular
• nominative

So the adjective must match it:

• tómur = masculine singular
• tóm = feminine singular
• tómt = neuter singular

That is why the sentence has gatan er tóm.

Because þegar introduces a subordinate clause, and subordinate clauses in Icelandic do not follow the same main-clause word order pattern.

In a main clause, Icelandic often has verb-second word order. But after a subordinating word like þegar, the order is more like:

• conjunction
• subject
• finite verb
• rest of clause

So:

• þegar gatan er tóm = when the street is empty

is the normal structure.

Yes. Hjóla is commonly used intransitively, meaning you can use it without a direct object.

So Hún hjólar simply means She bikes / cycles.

Then the sentence adds a prepositional phrase, á hjólastígnum, to say where she bikes.

The comma separates the main clause from the added clause that follows it.

Main clause:

• Hún hjólar alltaf á hjólastígnum

Added subordinate clause:

• jafnvel þegar gatan er tóm

In Icelandic, commas are often used to mark clause boundaries more clearly than in English. So this comma helps show that the second part is an added dependent clause giving extra information.